Computer for Gaming 1 Year old *

Hello, this computer was custom built by a friend of mine purely for gaming, but recently it has broken down, i am not sure what the problem is, everything works the fans spin, can hear the Hard disk working, but non of the USB ports are working, this is the reason i am selling it because i do not have the motivation and the time to fix it. -HD radeon 5850 Turbo graphics card -1TB Hard disk -MSI mother board -Two 2 GB DDR3 ram sticks -650w power supply -2 Fans+ the video card fan ad the power supply fan.